A　stable　3d-4f　heterometallic　cluster,　namely,　hydroxyquinoline),　has　been　solvothermally　synthesized　and　structurally　characterized.　The　compound　exhibits　an　interesting　structure　in　which　a　tetrahedron　based　on　4f　ions　interpenetrates　with　a　square　pyramid　based　on　3d　ions.　Besides,　a　unique　intermolecular　interaction　was　found　in　Dy4Ni5,　giving　rise　to　its　high　stability　not　only　when　it　is　in　the　solid　state　but　also　when　it　dissolves　in　organic　solvents.　In　addition,　the　magnetic　behavior　of　solid　Dy4Ni5　and　the　magneto-optical　activity　of　the　Dy4Ni5　solution　were　also　studied.